Attenuation of the Side Effect Profile of Regadenoson: Study With Aminophylline in Patients With Severe Kidney Disease Undergoing Myocardial Perfusion Imaging

Inclusion Criteria: * Adult patients referred to undergo a clinically-indicated regadenoson-stress myocardial perfusion imaging at Rush University Medical Center * Stage IV or V chronic kidney disease (GFR \< 30, hemodialysis, and/or peritoneal dialysis). Exclusion Criteria: * Patient refusal to participate * Known allergic reaction to aminophylline. * Pre-existing headache or acute/subacute GI illness with symptoms of diarrhea, abdominal discomfort, nausea or vomiting. * Any contraindication to aminophylline: hypotension, unstable cardiac arrhythmias and acute coronary symptoms. * Uncontrolled seizure disorder defined as more than 2 seizure episodes in the past 12 months or any seizure in the past week. * Pregnant or breast-feeding women. * Patients receiving anti-platelet agent dipyridamole (Persantine® or Aggrenox®).